Re: which part of cell controls the rate of metabolism of cell?

Dear Weddi:

The centers for cellular metabolism in eukaryotes, such as multicellular animals & plants, are the mitochondria organelles.  They are sometimes referred to as our "energy factories", and contain most of the proteins & enzymes that catalyze & control energy generation through a process known as cellular respiration.  The rate of this metabolic energy generation is controlled at 2 basic levels:

Intrinsic regulation controls metabolic rate in response to local changes in the levels of enzyme substrates or products.  For example, an increase in sugar availability may trigger an increase in its rate of catabolism.

Extrinsic regulation controls metabolic rate in response to signals from other cells.  For example, an increase in insulin secretion into the blood may trigger an increase in the rate of sugar catabolism for the whole organism, regardless of local sugar levels.

Finally, mitochondrial inheritance is unique & very interesting.  When an egg is fertilized, the mitochondria do not combine like the nuclear chromosomes do.  Instead, the mitochondria that are passed on to the offspring are generally only from the egg. This process is known as maternal inheritance, meaning that we inherit our mitochondria, & their inherent metabolic capabilities, only from our mothers.

Thanks for the great question,

Jeff Buzby, Ph.D.
CHOC Research Institute